1. Field of the Invention
The present invention generally relates to process control systems, and more specifically to a method and apparatus for testing of control strategies in a control system of a process control plant.
2. Related Art
A process control plant generally contains several equipment (e.g., boilers, filters, furnaces, coolers, etc.), which are used to implement a desired control process (e.g., oil refinery, manufacturing operation, etc.). Each equipment in turn generally includes devices such as actuators (such as valves and switches) and sensors, which are specifically operable facilitating various manufacturing objectives.
A control system is often employed to control such devices. The control system generally issues control commands to the devices on a network and receives the corresponding responses. The commands can change the state of the target device or request status information. The status information can be received without sending commands also, for example, when a variable value exceeds a pre-specified threshold. Additional commands may be issued based on the status information received and/or responses to various commands.
A control system is in general configured with various control strategies, which implement the desired control process by controlling the operation of devices (by issuing the commands noted above). The control strategies are specified by functional blocks connected in a desired manner. The functional blocks perform pre-specified computations (often referred to as an algorithm in the relevant arts, and referred to as control approach below) on the received set of input values, and generate output values associated with corresponding output variables.
There has been a recognized need to test the control strategies at least before deployment in production environments. In one prior embodiment, a tester is provided a suitable user interface to manually select a control strategy, set various variables of the selected strategy to desired values, and start the test for the test case.
Unfortunately, such manual approaches consume substantial amount of test time, and are susceptible to errors as well. The problems are compounded due to the fact that a large number of test cases may need to be used to comprehensively test a control system prior to deployment in a production environment.